Generally, a water purifier serves to filter harmful ingredients such as foreign materials or heavy metals included in water in a physical or chemical manner. A similar apparatus to the water purifier may include an ionized water apparatus, etc.
The water purifier may be directly classified into a direct type one that is directly connected to a faucet, and a storage type one configured to pass water contained in a vessel through a filter.
According to water purifying principles or methods, the water purifier may be divided into a natural filtration type, a direct connection filtration type, an ion exchange resin type, a distillation type, a reverse osmosis type, etc.
The natural filtration method is a method for purifying stored water by passing it through a ceramic filter by gravity, and the direct connection filtration method is a method for directly connecting a water purifier to a faucet. The ion exchange resin method is a method for removing metal dissolved in water from the water in a separation manner, by using an ionized exchange resin filter, and the distillation method is a method for purifying water by cooling vapor generated when boiling the water. And, the reverse osmosis method is a method for filtering impurities by passing water through a semi-permeable membrane with using a pressure.
This water purifier may be largely divided into a filtering unit for filtering contaminants from raw water, a water tank unit for storing purified water having passed through the filtering unit, and a discharging unit for discharging the purified water stored in the water tank unit.
However, in the conventional water purifier, a function of the filtering unit may be degraded according to the usage time or the usage amount. And, inner components of the water purifier, especially, components through which water passes or in which water is stored may have water stains or contaminant stains accumulated thereon. This may result in pollution of a user's drinking water.
To prevent these problems, the water purifier has been cleaned as a special person who cleans components of the water purifier (so-called, ‘Codi’) periodically visits the water purifier purchaser's home or company, so as to replace the filter by a new one.
However, in the conventional method for cleaning a water purifier by a Codi, a cleaning agent is put into the water tank unit, and then water stored in the water tank unit is discharged after a predetermined time has lapsed.
And, the cleaning agent remaining in the water tank unit is removed by supplying water to the water tank unit and then making the water discharged out by a user under the Codi's instructions.